Water-in-oil emulsion lubricant and hydraulic fluid



United States Patent O WATER-IN-OIL EMULSION LUBRICANT AND HYDRAULIC FLUID Charles E. Francis,,Martinez, Califi, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 17, 1961, Ser. No. 145,766

a I 11 Claims. (Cl. 252-336) This invention relates to improved fire-resistant hydraulic fluids. More particularly, it pertains to water-in-oil colliery hydraulic fluids and lubricants which are fire and, wear-resistant, stable and non-corrosive and to oil concentrates which are readily emulsifiable with large amounts of water.

Although it is known in the art that certain emulsions are useful as coolants and lubricants in metal working operations, the use of emulsions in hydraulic systems has been limited because of their inability to resist wear, their poor stability and their inability to pass. fire-resistant requirements for which such fluids are primarily used.

In colliery equipment such as various hydraulic machinery, e.g., winder brake mechanism and wagon tipper to hydraulic. jacks, pit props and roof bar straighteners, mechanical loaders and various other fluid drive mechanisms which are subject to load, shock and vibration, it is essential that the hydraulic fluid employed therein function properly and efliciently without the danger of being flammable or toxic.

A variety of so-called fire-resistant ,fluids are commercially available such as phosphate ester base fluids, but these have been found to possess poor lowtemperature viscosity-temperature properties, andthey are toxic. Water-glycol solution or various water-oil" emulsions have been found to have a tendency to form deposits and cause sistant to deterioration, inhibits corrosion and not cause wear. Still another object of this invention is to provide a water-mineral oil emulsion usable as lubricants and fire resistant hydraulic fluids for various equipment used in colliery hydraulic equipment.

These and other objectsare accomplished in accordance. with this invention by providing a highly aromatic high viscosity indeX mineral oil base concentrate which is readily emulsifiable with a large amount of water, and which contains two particular types of dissimilar nonionic surface active agents and an alkali metal dithiocarbamate or a mixture of alkali metal dithiocarbamate and alkali metal mercaptobenzothiazole, the metal portion being selected from the group consisting of sodium and potassium, all of the'additives being present in critical.

amounts. Oil concentrates of this invention are readily emulsified with large amounts of water (20-45%) to form a stable, fire resistant water-in-oil emulsion, particularly usefulin colliery hydraulic equipment.

If desired small amounts of polyvalent metal dithiocarbamates, the

7 metal portion of the compound beingselected from the group consisting of zinc, cadmium and/ or lead and an alkylene glycol or ether derivative thereofcan be added to the oil concentrate to improve emulsification and cold storagestability of the finished Water-in-oil' emulsion.

The highly aromatic mineral oil base should be one having a viscosity index (Dean Davis) of at least 80, preferably between 90 and 100. Mineral oil fraction should also be in the lubricating oil range and have a viscosity, as determined at 100 F., of from 75 to 250 "ice SUS, preferably between and and an aromatic content of from about 10% to about 30%.

A typical mineral oil base is a high viscosity index highly solvent refined mineral lubricating oil having the following properties.

Gr. API, 60 C. Color, ASTM 1 Pour point, F. 5 Flash, F., COC 370 Fire, F. 435 Viscosity, SUS at 100 F 103 Viscosity index 93 Neutralization No. 0.01 Components, percent w.:

n-Alkanes 21.8

Isoalkenes 11.8 Noncondensed cycloalkanes 24.9 Condensed cycloalkanes 12.4- Total saturates 70.9 Monoaromatics 13.6 Diaromatics 5.8 Triaromatics 4.0

Teteraaromatics 1.6 Pentaaromatics 0.2 Hexaaromatics Total sulfur compounds 3.9

Total 100.0

Sulfur analysis, percent w.:

Thiopenes Benzo- 1.7

Triaromatics 0.5

Teteraaromatics 0.4

Pentaaromatics Other sulfur compounds 1.3

Total 3.9

The two non-ionic surface agents and the metal com pounds defined above may be added to the mineral oil and these compounds are (1) a monoester of a long chain fatty acid having at least 3 carbon atoms and an inner ether of aliphatic polyhydric alcohols such as hexahydric alcohols and (2) a polyalkylenoxy phenoxy alkanol, and (3) an alkali metal dithio'carbomate or a mixture of (a) alkali metal thiocarbamate and (b) alkali metal mercaptobenzothiazole. Each of these additives must be present in critical amounts of which the monoester (1) be used in amounts ranging from 1% to 4%, preferably from 1.5% to 3% and the polyalkylenoxy phenoxy alkanol (2) is used in amounts ranging from 0.5% to 3%, preferably from 1% to 2%, and (3) isused in amount of from 0.01% to 1.0%, each by weight.

In themonoester non-ionic surface agent the inner ether alcohol is prepared by partially dehydrating polyhydric alcohols which results in the conversion of the polyhydric alcohol to inner ether polyhdric compounds having 1 or 2 ethers and 4 to 6 hydroxyl groups in the molecule in the manner described in US. Patent 2,322,820. Compounds of this type are exemplified by sorbitan, mannitan, xylitan, dulcitan, etc. Fatty acids which are used to form the monoesters of the inner ether polyalcohols are saturated and unsaturated fatty acids having at least 8 carbon atoms, preferably from 12 to 18 carbon atoms, such as lauric, stearic, oleic, linoleic, ricinoleic acids and the like. Monoesters of this type include sorbitan monolaurate, sorbitan rnonostearate, sorbitan monooleate, sorbitan monoricinoleate, mannitan monolaurate, mannitan monooleate, and mixtures thereof. Compounds of this type are available commercially as Span 20, 60, or 80 from the Atlas Powder Company.

The second essential additive is an oil-soluble alkyl potassium mercaptobenzothiazole.

phenoxy polyalkylene glycol having the formula R-phenyl (OR') OR"OH, wherein n is an integer of from 2 to 6, preferably 3 to 4, R is an alkyl radical of 4 to 20 carbon atoms, preferably 4 to 12, and R and R are the same or different alkylene groups such as ethylene or propylene groups, they are preferably the same, and preferably ethylene; Compounds of this type are C alkyl phenoxy(alkoxy) alkanols exemplified by isobutylphenoxy tetraethyleneoxy ethanol, diisobutylphenoxy tetraethyleneoxy ethanol, nonylphenoxy tetraethyleneoxy ethanol, octylphenoxy hexaethyleneoxy ethanol, diisobutylphenoxy tripropyleneoxy propanol, and mixtures I thereof.

' it can be hydrogen; it is desirable that both R radicals are alkyl radicals'from 1 to 16 carbon atoms in which the alkyl radicals'can be of same di'lferent chain length and structure, and it is preferred that the Rs are C alkyl radicals of the samechain length but different structure.

Examples of such salts are sodium and/ or potassium dimethyl, dibutyl, diamyl, dihexyl, diisobutyl, dioctyl, dicyclohexyl, dicresyl, dithiocarbamates of which the preferred are sodium dimethyl dithiocarbamate, sodium dibu-tyl dithiocarbamate, sodium diisobutyl dithiocarbamate and sodium diamyl dithiocarbamate.

The other portion of mixture (3) includes sodium or Preferred mixture of (3) includes 90-l0tmixtures of sodium methyl dithio carbamate and sodium mercaptobenzothiazole, sodium dibutyl dithiocarbamate and sodium mercaptobenzothiazole, sodium diaryl dithiocarbamate and sodium mercaptobenzothiazole, sodium diisobutyl dithiocarbamate and sodium mercaptobenzothiazole, potassium dibutyl dithiocarbamate and potassium mercaptobenzothiazole, andpotassium. diamyl dithiocarbamate and potassium mercaptobenzothiazole. I

In addition tothe above essential additives, stability I and emulsifiability can be improved by addition of small amounts (0.010.5% each) ofpolyvalent metal dithiocarbamate and alkylene glycol or its ether derivatives.

The .polyvalent metal dithiocarbamates includes the zinc, cadmium or lead salts of N- or N,N'-C alkyl substituted dithiocarbamic. acid such as zinc, cadmium, or lead clipropyl mono and dithiocarbamate, dibutyl mono anddithiocarbamate, diamyl mono and dithiocarbamate,

.dihexyl Emono and dithiocarbamate, dioctyl mono and dithiocarbamate, di-2-ethylhexy1 mono and dithiocarbamate, di-isobutylmono and .dithio-carbamate, diisoamyldithiocarbamate mono and N-amyl-N-methyl mono and dithiocarbamate, N-methyl-N-octyl mono and dithiocarbamate, N-octyl-N-butyl mono and dithiocarbamate, N-n-amyl-N-2-methylbutyl dithiocarbamate, N-n-amyl- N"-3-methylbutyl dithiocarbam-ate, N-ootyl-N'-2-ethyl- -hexyl dithiocarbamate, N-ethyl-N phenyl mono and dithiocarbamate, dicyclohexyl mono and dithiocarbamate, diphenyl mono and dithiocarbamate, and the like.

The alkylene glycols and the ether derivatives thereof includes ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol,- hexylene glycol and mixtures thereof.

In addition to the above essential additives it is preferred to use in such compositions small amounts of from about 0.01% to about 2%, preferably from about 0.2% to about 1% of oil soluble antioxidants. The antioxidants include phenolic and aromatic soluble antioxidants. The antioxidants includes phenolic and aromatic amine compounds. The phenolic compounds are illustrated by the alkyl phenols, e.g., diand trialkyl phenols, for instance 2,4-, 2,3-, 3,4-, 2,6- and 3,5-diamyl phenol, 2,4-dirnethyl- 6-ter t. butylphenol, 2,6-ditert.butyl-4-methylphenol,j as well as bisphenols such as 4,4'rnethylene-bis(2,6-ditert. butylphenol). The amines are illustrated by 'arylamines such as phenyl-alpha-naphthylamine or phenyl-betanaphthylamine.

Illustrative examples of mineral oil bases of this invention which are emulsified .with from about20% to about 45%, preferably from about 30% to about 40% of Water to form a stable fire-resistant hydraulic fluid are presented below. Percent Wt.

Composition A:

Sorbitan mono-cleats 2 Diisobutylphenoxy-(ethoxy) ethanol 1 Sodium dimethyl dithiocarbamate-sodium mercaptobenzothiazole, /10% mixture 0.5 Mineral lubricating oil (X) Balance Composition Bz) Sorbitan mono-oleate 2 Diisobutylphenoxy(eth-oxy) ethanol 1 Sodium dibutyl dithiocarbamate-sodium mercaptobenzothiazole, 50% mixture 0.5 Miner-a1 lubricating oil (X) Balance Composition C:

Sorbitan mono-Oleate 2 -Diisobutylphenoxy(ethoxy) ethanol 1 Sodium diamyl dithiocarbamatesodium' mercaptobenzothiazole, 50% mixture 0.5 Mineral lubricating oil (X) Balanc Composition D:

. Sorbitan mono-oleate 2 Diisobutylphenoxy(ethoxy) ethanol 1 Sodium dimethyl dithiocarbamate 0.01 2,6-ditertbutyl-4-methyl phenol 0.2 Phenyl-alpha-naphthylamine 0.1 Mineral lubricating oil (X) Balance Composition E:

Mannitan mono-oleate 2 Diisobutyl-phenoxy(ethoxy) ethanol 1 Sodium dimethyl dithiocarbamatesodium mercaptobenzothiazole', 90/10% mixture 0.5 2,6-ditert.butyl-4-methyl phenol 0.2 Phenyl-alpha-naphthylamine 0.1 Mineral lubricating oil (X) Balance Composition F:

Mannitan mono-oleate 2 Nonylphenoxy(ethoxy) ethanol 1 Sodium dimethyl dithiocarbamate-sodium mercaptobenzothiazole, 90/10% mixture 0.5 4,4-methylene (2,6-ditert.butylpheno-l) 0.2 Phenyl-alpha-naphthylamine 0.1 Mineral lubricating oil (X) Balance Composition G:

Sorbitan mono-oleate 2 Diisobutylphenoxy(ethoxy) ethanol 1 Sodium dimethyl dithiocarbamate-sodium mercaptobenzothiazole, 50% mixture 0.5 2,6-ditert.butyl-4-methyl phenol 0.2 Phenyl-alpha-naphthylamine 0.1 Cadmium diamyl dithiocarbamate 0.025 Mineral lubricating oil (X) Balance Composition H:

Sorbitan mono-oleate 2 Diisobutylphenoxy(et-hoxy) ethanol 1 Sodium dimethyl dithiocarbamate 0.01 2,6-ditert.butyl-4-methyl phenol 0.2 Phenyl-alpha-naphthylamine 0.1 Zinc diamyl dithiocarbamate 0.025 Ethylene, glycol 0.2

Mineral lubricating oil (X) Balance The finished emulsion fluid is prepared by slowly adding to the oil base composition such as A, B, C, D, E, F,'G

or H from 20% to 45% based on the total composition,

an aqueous base, such as water which may or may not contain 0.1% to 1% of a corrosion or wear inhibitor such as water-soluble inorganic nitrites, nitrates, chromates, phosphates or watersoluble low molecular weight salts such as alkali metal-or alkaline earth metal (Na, K, Ca, Ba) acetate or propionate. The water-in-oil emulsion can be mixed by any suitable means such as by air agitation, propeller agitation orby passing through a colloid mill until a homogeneous stable water-in-oil emulsion is formed; For economical reasons, the water is added to the oil in desired amounts at the time the emulsion is to be used, although a stable water-in-oil emulsion can be prepared and stored for :a moderate period.

A finished water-in-oil emulsion (Composition I) was prepared by admixing 60% of composition D with 40% Water and the mixture was passed through a colloid mill until a stable homogeneous water-irr-oil emulsion was formed.

Other finished compositions include:

Percent Composition 11-- 'Water 30 Composition A 70 Composition III-.-

Water containing 0.1% Ca acetate 4'0 Composition G 60 Composition IV- Water containing 0.1% NaNO 35 Composition C 65 Composition V Water 40 Composition H 60 The outstanding emulsion stability properties of these compositions is demonstrated by compositions I and V in Table 1 in comparison with composition W* which does not contain a metal carbamate. The stability was determined by measuring the amount of oil and water separation at 140 F. from a 100 ml. sample. Also in a Vickers Hydraulic Pump Test similar to that described in Lubrication Engineering, February 1949, pages 16-17, negligible wear was noted using compositions I and V after 1000 hours testing, whereas compositions X* and Y* resulted in phase separation in from about 1 to 2 days.

Compositions of the present invention such as compositions I through V are fire-resistant passing over 50 cycles as determined by the Pipe Cleaner Test described in Lubricating Engineering, March-April 1955, pages 86- 87 while a neat mineral oil or a mineral oil containing 4% *Composition W: [water-in-oil emulsion comprising 40% water plus 60% mineral oil composition containing 2% sorbitan monooleate (Span 80)+1% diisobutylphenoxflothoxyh ethanol+0.2% 2,6-ditertiarybutyl- 4-methyl phenol+0.l% phenyl alphanephthylamine].

*Composition X: [water-in-oil emulsion comprising 40% water+60% mineral oil composition containing +15% polyethylene substituted sorbitan monooleate (Tween 81)+0.15% glycerol monoo1eate+0.12% sulfurized oleic acid].

*Composition Y: [oil-in-water emulsion comprising 50% water-+50% mineral oil composition containing 20% Ne petroleum sulfonate, 1% ricinoleic acid, 1% hexylene glycol, 1% lard oil, 2% water, 0.3% Dowicide- O, 0.1% sodium hydroxide and the balance mineral oil].

each of Ca petroleum sulfonate and/or Ca C1242 alkyl salicylate ignited after 5 cycles.

I claim as my invention:

1. A water-in-oil emulsion lubricant and hydraulic fluid which is fromabout 20% to about 45 water'phase and from about 55% to 80% oil phase, the oil phase being essentially a 80-100 VI mineral oil having a viscosity in the range of from 75 to 250 SUS at 100 F. containing (1) from about 1% to about 4% of a monoester of a long chain fatty acid having from 8 to 18 carbon atoms and an inner ether of an aliphatic polyhydric alcohol having 1-2 ether and 4-6 hydroxyl groups, (2) from about 0.5% to about 3% of an 0ilsoluble C alkyl'phenoxy(C alkoxy) C alkanol, and (3) from about 0.01% to about 1% of a material selected from the group consisting of alkali metal C alkyl substituted dithiocarbamate and a mixture of 10-90% of an alkali metal C alkyl substituted dithiocarbamate and 90-10% alkali metal mercaptobenzothiazole.

2. A water-in-oil emulsion lubricant and hydraulic fluid which is from about 20% to about 45 Water phase and from about 55% to about 80% oil phase, the oil phase being essentially a 80-100 VI mineral oil having a viscosity in the range of from 75 to 250 SUS at 100 F. containing 1) from about 1.5% to about 3% of a monoester of a fatty acid having from 12 to 18 carbon atoms and an inner other of an aliphatic hexahydric alcohol having 1-2 ether and 4-6 hydroxyl groups, (2) from about 1% to about 2% of an oil-soluble C alkyl phenoxy(ethoxy) ethanol, and (3) from about 0.01% to about 1% of a material selected from the group consisting of an alkali metal C alkyl substituted dithiocarbamate and a mixture of 25-75% of an alkali metal C alkyl substituted dithiocarbamate and -25 of an alkali metal mercaptobenzothiazole.

3. A water-in-oil emulsion lubricant and hydraulic fluid which is from about 20% to about 45% water phase and from about 55 to about oil phase, the oil phase being essentially a 80-100 VI mineral lubricating oil having a viscosity in the range of from to SUS at 100 F. containing from about 1.5% to about 3% .of a sorbitan monooleate, from about 1% to about 2% of an alkyl mixture of phenoxy(ethoxy) ethanol and from about 0.01 to about 1% of a mixture of 10-90% of sodium dimethyldithiocarbamate and 90-10% of sodium mercaptobenzothiazole.

4. The composition of claim 2 containing in the emulsion from 0.01% to 2% of an oil-soluble antioxidant selected from the group consisting of alkyl substituted simple phenol and phenyl-alpha-naphthylamine and mixtures thereof.

5. The composition of claim 2 containing in the emulsion from about 0.01% to about 1% of an oil-soluble polyvalent metal N,N'-C alkyl substituted dithiocarbamate, the metal being selected from the group consisting of zinc, cadmium and lead.

6. The composition of claim 3 containing in the emulsion from 0.01% to 2% of an oil-soluble antioxidant selected from the group consisting of alkyl substituted simple phenol and phenyl-alpharnaphthylamine and mixtures thereof.

7. The composition of claim 3 containing in the emulsion from about 0.01% to about 1% of an oil-soluble polyvalent metal N,N-C alkyl substituted dithiocarbamate, the metal being selected from the group consisting of zinc, cadmium and lead.

8. A Water-in-oil emulsion lubricant and hydraulic fluid which is from about 30% to about 40% Water phase and from about 70% to about 60% oil phase, the oil phase being essentially a 80-100 VI mineral lubricating oil containing from about 1.5% to about 3% of sorbitan monooleate, from about 1% to about 2% of an oil-soluble diisobutylphenoxy(ethoxy) ethanol and from about 0.01% to about 1% of a 50-50 mixture of sodium dimethyl dithiocarbamate and sodium mercaptobenzothiazole.

a '7 8 I 9. The composition of claim 8 containing in the emul: butylA-methylphenol, phenyl-alphanapthylamine and eth- Sion from about 0.01% to about 1% each of an oil-soluble 3 1 116 glycol. alkylphenol, an oil-soluble ar'ylamine and polyvalent metal N,N'-,C alkyl substituted dithiocarbamate, the metal be- References Cited by theiExammer ing selected frorn'the group consisting of zinc, cadmium UNITED STATES A E T and lead; 2,625,509 1/53 Lang 252-495 10.1 Thecom-position of claim 8 containing in the emul- 5 1 6/54 3 F 25275 sion from about"0.01% to about 1% each of 2,6-ditert.-

g 2 5 2 7 buty1-4-methylpheno1, phenyl-alpha-naphthylamine and 10 v mums N 7 X zinc diamyldithiocarbamate. JULIUS GREENWALD; Pimary Examiner.

11. The composition of claim 8 containing in the emul- JOSEPH LIBERMAN ALBERT '11 MEYERS sion from about 0.01%v to about 1% each of 2,6-ditert.- 1 E in 

1. A WATER-IN-OIL EMULSION LUBRICANT AND HYDRAULIC FLUID WHICH IS FROM ABOUT 20% TO ABOUT 45% WATER PHASE AND FROM ABOUT 55% TO 80% OIL PHASE, THE OIL PHASE BEING ESSENTIALLY A 80-100 VI MINERAL OIL HAVING A VISCOSITY IN THE RANGE OF FROM 75 TO 250 SUS AT 100*F. CONTAINING (1) FROM ABOUT 1% TO ABOUT 4% OF A MOOESTER OF A LONG CHAIN FATTY ACID HAVING FROM 8 TO 18 CARBON ATOMS AND AN INNER ETHER OF AN ALIPHATIC POLYHYDRIC ALCOHOL HAVING 1-2 ETHER AND 4-6 HYDROXYL GROUPS, (2) FROM ABOUT 0.5% TO ABOUT 3% OF AN OIL-SOLUBLE C4-20 ALKYL PHENOXY (C2-3 ALKOXYL)4-6 C2-3 ALKANOL, AND (3) FROM ABOUT 0.01% TO ABOUT 1% OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL C1-12 ALKYL SUBSTITUTED DITHIOCARBAMATE AND A MIXTURE OF 10-90% OF AN ALKALI METAL C1-12 ALKYL SUBSTITUTED DITHIOCARBAMATE AND 90-10% ALKALI METAL MERCAPTOBENZOTHIAZOLE. 